Effort Metabolism of Lateral Muscles in Carp

Abstract

Effort induced by direct electrical stimulation of the lateral musculature of the carp led to effects which differed from one muscular tissue to another. With moderate effort, in the white muscle the glycogen concentration decreased and the pyruvate concentration increased; in the red muscle, the glycogen and pyruvate concentration did not change, but the amount of lactate and the oxygen consumption increased. With exhausting effort, the white muscle showed a decrease of glycogen and pyruvate, a great increase of lactate, without any significant modification of oxygen consumption; in the red muscle, there was a slight decrease of glycogen, an enormous rise of lactate, and a slight decrease of oxygen consumption. The sole modification observed in the liver was the increase of the lactate content after stimulation. Hypoxic conditions induced a great increase of the lactate:pyruvate ratio in the liver and in the red muscle, but not in the white. The findings suggest that the red muscle is a "burning place" of catabolites produced in the white muscle.